1. Field of the Invention
The present invention relates generally to hose couplings, and in particular to a coupling system for a corrugated, flexible metal hose.
2. Description of the Related Art
Hoses, conduits, pipes and the like are commonly used to convey a wide variety of different fluids. Many such applications require flexible metal hose to accommodate relative movement between system components being connected. For example, fuel lines intended to convey gaseous fuels (e.g. natural gas or propane), are commonly constructed of flexible metal hose.
To accommodate relative movement in gaseous fuel systems, the fuel lines are often flexible. For example, flexible corrugated metal hose is commonly used for connecting a wide variety of gas-fired appliances to gas sources. Such corrugated metal hose has several advantages, including flexibility and an ability to extend and contract. Moreover, it is relatively inexpensive to manufacture and its use tends to reduce the need to precisely position a gas-fired appliance with respect to a gaseous fuel source. Therefore, installation of gas-fired appliances can be facilitated because exact placement is not necessary and approximate positioning can be accommodated by a flexible gas line. Gas lines can be permanently installed in a building and routed through the structure from a gas source to the general location of gas-fired equipment and appliances. Less-permanent gas lines are often used for making the final connections to the appliances themselves, and are commonly referred to as "whips". Gas line whips are commonly fabricated from lengths of corrugated, flexible metal hose. Both permanent gas lines and whip gas lines require secure end connections. Whip gas lines are commonly used with appliances which are subject to some degree of movement, such as gas-fired dryers, ovens and the like.
Design criteria common to such gas lines include providing relatively secure, fluid-tight seals and providing sufficiently strong end connections to avoid a separation or pull-out of the line from the appliance or other equipment. In the case of a gaseous fuel line, leaks can be very dangerous since many gas fuels are by nature both toxic and highly flammable. Thus, to avoid accidental gas poisoning or explosion, structurally secure systems are very important.
In the case of rigid gas lines, sufficient material thickness is often present to provide threaded fittings, which tend to be relatively secure and leak-resistant. With corrugated flexible metal hose, however, the material is often relatively thin-walled and thus not sufficiently thick to accommodate threading.
To address the problem of providing secure fittings on flexible metal hose, various coupling systems have been devised. These include a variety of compression fittings, washers, O-rings and gaskets. However, heretofore there has not been available a coupling system for a corrugated flexible hose with the advantages and features of the present invention.